Bristol Cars - Owners and Enthusiasts Forum  

Go Back   Bristol Cars - Owners and Enthusiasts Forum > Bristol Forums > 6 cyl Bristol cars

6 cyl Bristol cars Type 400 to 406 - restoration, repair, maintenance etc

401 gearbox

Reply
 
Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 17-02-20, 10:18 PM
Member
 
Join Date: Jul 2019
Location: Westward Ho, Devon
Posts: 30
Default Slow But Steady Progress

Just an update if anybody is interested. Once the gearbox was out, I took off the clutch and flywheel, the latter having now been skimmed and refitted. A complete new MGB clutch is in a box awaiting fitment. I decided that although the main reason for removing the box was to fix the clutch judder that I might as well improve the second gear synchro and a tendency to jump out of third on the overrun. This is where everything seemed to go into SLOW MO...... but last week some progress was made. Fitted proper thickness circlips to prevent the shaft moving axially, obtained a new old stock complete 2nd gear synchro hub with second gear from Bristol Cars, BUT it seems I also need the first gear freewheel hub as mine does not fit so again Bristol Cars are sending me a NOS one. Fingers crossed this one is a good fit! I did get a quote from a local precision engineering company to 3D scan to splines and do something called spark reduction on the existing splines which is very high tech but it seems eye wateringly expensive.
Reply With Quote
  #2 (permalink)  
Old 11-03-20, 09:00 AM
Member
 
Join Date: Jul 2019
Location: Westward Ho, Devon
Posts: 30
Default Gearbox oil

Refitting my 401 gearbox this week at long last. It is the early type and what is the advice regarding oil grade and type of oil? I also have a Laycock overdrive so again any advice on best oil choice?
Reply With Quote
  #3 (permalink)  
Old 12-03-20, 08:40 PM
Member
 
Join Date: Jul 2019
Location: Westward Ho, Devon
Posts: 30
Default Lubrication

Well a bit disappointed at not receiving any views on oil grades so have done my own research and will be using Castro’s XXL which is straight40 grade in the gearbox and overdrive which shares the same oil anyway. I managed to get the box back in today with the help of my son in law and tomorrow will be bolting everything together. Looking forward to synchronised gear changes and smooth take offs. We shall see.
Reply With Quote
  #4 (permalink)  
Old 16-03-20, 03:10 PM
Member
 
Join Date: Mar 2009
Location: West Wales.
Posts: 477
Default

The 405 handbook suggests a an SAE30 for the gearbox and overdrive, I asked Brian at BCL what was best for my non overdrive box in the 401 and he suggested the same 20/50 oil we are using in the engine.
Castrol XXL is one of the oils recommended for the gearbox in the late 401's and 403's so I would have thought should be ok.
Reply With Quote
  #5 (permalink)  
Old 12-04-20, 11:04 AM
Member
 
Join Date: Jul 2019
Location: Westward Ho, Devon
Posts: 30
Default Gearbox tested

Now I am grounded like us all, I am attending to several tidying up jobs on the Bristol as sick of gardening! I did take the 401 for a brief test drive before lock down with Castrol XXL 40 in the gearbox and overdrive and was very pleased that all the synchro worked and the gears shifted nicely. The change was a bit notchy so I have since slackened off the detent springs slightly but otherwise very pleased. The clutch is also now super smooth so clearly the minute skimming of the flywheel was just what was needed. Such a shame we are missing this weather but we fully support the stay home policy.
Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


All times are GMT. The time now is 04:51 AM.


This is the live site

Search Engine Friendly URLs by vBSEO 3.6.0 PL2